Investigating the role of zeolite supports in Ni-based catalysts for CO₂-methanation using in situ/operando XAS–GC-MS

Abstract

Nickel (Ni) is regarded as the most effective non-noble metal catalyst for CO₂ methanation. Its performance is strongly influenced by support material and Ni reducibility. This study investigates the impact of zeolite types (ANA, LTA, and ZSM-5) on the reducibility and catalytic performance of 5 wt% Ni catalysts, compared with SiO₂. Reducibility, measured via in situ X-ray absorption spectroscopy (XAS) from 100 to 450 °C, followed the order: 5Ni/ZSM-5 > 5Ni/ANA > 5Ni/LTA > 5Ni/SiO₂. Catalytic testing in a fixed-bed flow reactor revealed the highest CO₂ conversion at 400 °C, following the order: 5Ni/LTA > 5Ni/ZSM-5 > 5Ni/ANA > 5Ni/SiO₂. Zeolite-supported catalysts achieved significantly higher CH₄ selectivity compared to 5Ni/SiO₂, with the trend: 5Ni/LTA > 5Ni/ZSM-5 > 5Ni/ANA ≫ 5Ni/SiO₂. Comprehensive characterization using X-ray diffraction, N₂ adsorption-desorption, and X-ray photoelectron spectroscopy was conducted to analyze catalyst properties. The CO₂ methanation mechanism was deduced using data from in situ XAS-MS. These findings demonstrate that zeolite-supported Ni catalysts, particularly 5Ni/LTA, exhibit superior reducibility and catalytic performance, advancing the development of efficient materials for CO₂ conversion.